full-write.c

/* full-write.c -- an interface to write that retries after interrupts Copyright (C) 1993, 1994, 1997, 1998, 2000 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. Copied largely from GNU C's cccp.c. */#include "dcfldd.h"#if HAVE_CONFIG_H# include <config.h>#endif#include <sys/types.h>#if HAVE_UNISTD_H# include <unistd.h>#endif#include <errno.h>#ifndef errnoexternint errno;
#endif/* Write LEN bytes at PTR to descriptor DESC, retrying if interrupted. Return LEN upon success, write's (negative) error code otherwise. */int
full_write (int desc, constchar *ptr, size_t len)
{
int total_written;
total_written = 0;
while (len > 0)
{
int written = write (desc, ptr, len);
/* write on an old Slackware Linux 1.2.13 returns zero when I try to write more data than there is room on a floppy disk. This puts dd into an infinite loop. Reproduce with dd if=/dev/zero of=/dev/fd0. If you have this problem, consider upgrading to a newer kernel. */if (written < 0)
{
#ifdef EINTRif (errno == EINTR)
continue;
#endifreturn written;
}
total_written += written;
ptr += written;
len -= written;
}
return total_written;
}